This SBIR is for the development of an automated color based micronuclei assay system based on results of a prototype MSDOS color analysis system. The system will automatically locate and count polychromatic erythrocytes (PCEs), micronucleated polychromatic erythrocytes (MPCEs) and normochromatic erythrocytes (NCEs). During Phase I, a number of critical variable parameters previously developed will be adapted into a user-friendly interactive program capable of rapidly selecting the appropriate parameters for each new slide preparation. These parameters include: the level of background strain; criteria for acceptable erythrocyte size range and roundness; and color discrimination. Color discrimination is the key element for differentiation. The system will be implemented on a Mac IIFX computer. It will include a capability to automatically process multiple slides into a report complete with statistical analysis. The Phase I final report will include the results of a test of the system. The test set-up and evaluation will be conducted by a consultant.